SOLUTION: Simplify {{{(1+tan^2(y))cos^2(y)}}}

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Question 1200880: Simplify %281%2Btan%5E2%28y%29%29cos%5E2%28y%29
Found 2 solutions by Theo, MathTherapy:
Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
start with (1 + tan^2(y)) * cos^(y)
simplify to get 1 * cos^2(y) + tan^2(y) * cos^2(y)
replace tan^2(y) with sin^2(y)/cos^2(y) to get:
cos^2(y) + sin^2(y)/cos^2(y) * cos^2(y)
simplify to get:
cos^2(y) + sin^2(y)
since that is equal to 1, your solution should be that the simplified expression is equal to 1.

Answer by MathTherapy(10557) About Me  (Show Source):
You can put this solution on YOUR website!


Simplify %281%2Btan%5E2%28y%29%29cos%5E2%28y%29

          ----- Substituting sec2(y) - 1 for tan2(y) 

          ----- Substituting 1%2Fcos%5E2%28y%29 for sec2(y)